Roll of pressure-sensitive adhesive striping tape



Nov. 3, 1953 c. J. CALABRESE ROLL OF PRESSURE-SENSITIVE ADHESIVESTRIPING TAPE Filed Aug. 15. 1949 J? May L AZZ'orrZeys Patented Nov. 3,1953 2,657,795 ICE ROLL OF PRESSURE-SENSITIVE ADHESIVE STRIPING TAPECarl J. Calabrese, St. Paul, Minn., assignor to Minnesota Mining &Manufacturing Company, St. Paul, Minn., a corporation of DelawareApplication August 15, 1949, Serial No. 110,272

1 Claim.

This invention relates to a roll of normally tacky andpressure-sensitive adhesive tape suitable for the masking of surfacesprior to painting of stripes and similar designs thereon. The rollconsists of a series of three, five, or a higher odd number ofcontiguous individual strips of masking tape wound on a single core, asdescribed more in detail hereinbelow.

The use of normally tacky and pressure-sensitive adhesive tape (maskingtape) for masking or protecting areas to be left unpainted, and formaking sharp lines of demarcation between differently colored paintedareas, is well known in the painting and decorating art. Such maskingtapes have been described in U. S. Patents Nos. 1,760,820,, 2,227,444,2,236,527, 2,410,078, 2,410,089, 2,438,195. They have a unified paperbacking coated on the inside face with a rubberresin typepressure-sensitive adhesive which is stably and aggressively tacky.These tapes can be unwound from rolls without delamination or offsettingof adhesive.

Where narrow painted stripes are required in a surface, two separatestrips of such masking tape are commonly placed separately along the twoedges of the proposed stripe. Paint or lacquer is then applied, as bybrushing or spraying, and the strips of tape are removed, leaving asharp-edged line or stripe of the paint or equivalent coating materialalong the unmasked area. The method requires two separate applicationsof tape and frequently results in uneven striping, since it is difiicultto space the strips of tape accurately. v

A previously proposed improvement in the striping art contemplatesplacing two strips of adhesive-coated tape and an intervening uncoatedspacing strip on an adhesive-coated carrier web to provide a two-layertape construction. The exposed adhesive-coated surface of the two-layertape is pressed against the surface which is to be painted, and theadhesive-coated carrier web, together with the adhering spacing strip,is peeled away, leaving the two lengths of adhesive tape adhered to thesurface and in accurately spaced position for striping. Such a two-layertape is bulky in the roll, requires double the amount of adhesive neededfor the functional use of the tape, and in addition is diflicult toassemble.

In another construction, a length of masking tape capable of being tornlongitudinally along straight lines is employed in preparation forstriping, a central longitudinal section being torn from the adheredtape to provide a masked stripe area for painting. Tape having an easilytorn cloth backing is one example of such a material. The torn edges ofthe cloth produce irregularities or fuzziness in the edges of the paintstripe, a condition which prevents the use of such methods wheresharp-edged paint lines or stripes are required, as is usually the case,

It is therefore an object of the present invention to provide means formasking a sharp-edged stripe area rapidly, accurately and economically.

This and other objects are accomplished, in

accordance with my invention, by assembling a plural odd number ofindividual strips of normally tacky and pressure-sensitive masking tapein edge-to-edge relationship and wound in convolute roll form on asingle core, in such a way that the tacky adhesive layers of theseparate strips become cohered together along the contiguous edges andhold the strips in that relationship during unwinding from the roll andapplication of the composite tape to a surface to be decorated. Thecohesive bond between contiguous edges is readily and cleanly brokenupon removal of the central strip or strips prior to application ofpaint or analogous coating. The discovery that edge cohesion betweenadhesive layers in a multiple-strip structure such as hereinabovedescribed is sufficient to permit the composite tape being unwound fromthe roll and applied to surfaces without preliminary separation of theindividual layers forms the basis of the present invention, and isparticularly sur-' prising in view of the complicated and less effectivemethods which, prior to this invention, were considered to be essentialin producing the desired results.

The accompanying drawing is a perspective view of a roll of the slittedtape and illustrates its use.

This drawing indicates the formation of a painted curved stripe I0 on aflat surface I I, such as a portion of an automobile body, with the aidof a composite striping tape such as hereinbefore described, andconsisting of masking strips I2 and I3, and. spacing strip I4, the threestrips being in edge-to-edge relationship and wound up in convolute rollform on a single core I5. In the figure, the central strip I4 isrepresented as being partly stripped or peeled back from between maskingstrips I2 and I3, thus exposing the normally tacky andpressure-sensitive adhesive surface I6. A coating of paint or lacquer I1is applied over the area of surface II thus exposed and over theadjacent areas of tape strips I2 and I3. These latter strips aresubsequently also removed by peeling, as indicated, the adhesive-coatedsurfaces I8 ad I9 of the strips I2 and I3 being thus exposed, leavingthe paint stripe I 0 in place on the surface I I. The paint stripe I3has sharply defined edges because of the complete absence of tearing andfuzzing of the fibrous backing of the tape along the lines between theseveral individual sections, and is of constant width because of the useof the spacing strip I4.

While constant width stripes are a feature of the preferred embodimentof the invention illustrated in the drawing, it will be apparent thatareas having desired re-occurring irregularities may be defined bysuitable modification of the composite tape. For example, slitting maybe in regular or irregular wavy or zigzag lines rather than in straightlines as shown; or various other patterns may be provided. Multiplestripes or designs may also be obtained, using composite tapes havingmore than one removable spacing strip. While mechanical dispensers forattaching the composite tape to various surfaces may be employed ifdesired, the product of this invention is easily and quickly applied byhand, and provides a means of obtaining, by unskilled amateur paintersand decorators, accurately dimensioned, smooth and sharply definedpainted stripes and patterns.

One preferred way in which the tape roll of the present invention mayreadily be assembled is by slitting the several individual strips ofmasking tape from a wider strip simultaneously and then winding themdirectly on a single core or reel. Several composite rolls may thus beproduced simultaneously from a single stock roll of adhesive-coatedtape. Preferably, a thin and flexible masking tape comprising a layer ofnormally tacky and pressure-sensitive adhesive firmly bonded to onesurface of an impregnated creped paper unified fibrous backing, which iscoated on the other surface with a low-adhesion backsize, is used as thebase stock. slitting may be accomplished by means of circular knivesrunning over a hardened score roll, the tape being passed between theknives and the hardened surface. When first slit, the individual stripsare completely severed from each other. After they have been wound up inthe roll, and particularly after sufficient storage time has elapsed toallow the normally tacky and pressure-sensitive adhesive to flowslightly, the individual strips are found to be cohered together alongthe contiguous slit edges to such an extent that the composite strip maybe unwound from the roll and applied to surfaces without separation.Individual strips may then be lifted from the surface and disengagedfrom the composite strip, without roughening the edges of the adjacentindividual strips and without disturbing their placement, to provide anarea having definite and sharp boundaries and which is ready for paintapplication.

The adhesive may be one of the various rubber-resin typepressure-sensitive tape adhesives, well known in the art, which arewater-insoluble and aggressively tacky. Various examples are given inthe previously cited patents. These adhesives have a rubbery base ofnatural or synthetic rubber which provides cohesion (internal strength)and elasticity (a retractive force when stretched and retraction whenreleased after stretching) and this rubber base is modified by blendingwith a compatible tackifier resin (such as rosin or ester gum) whichserves to increase adhesion (tackiness) and decrease cohesion, with anattendant increase of stretchiness (elongation under low stresses) anddecrease of elasticity. These rubber-resin tape adhesives have a properfour-fold balance of adhesion, cohesion, stretchiness and elasticity,which permits adhesive tape coated therewith to be aggressively andstably tacky and yet be capable of being stripped back from smoothsurfaces to which temporarily applied without delamination or offsettingof adhesive. These tape adhesives are termed eucohesive by which it ismeant that they are more cohesive than adhesive such that offsetting ortransfer of adhesive material does not r s when the tape coatedtherewith is unwound from rolls or removed from surfaces to whichtemporarily applied, and the tape can be handled without transfer ofadhesive material to the fingers. Certain synthetic polymers areinherently tacky and eucohesive and possess the above-mentioned fourfoldbalance of properties, and can be used as pressure-sensitive tapeadhesives, thus being equivalents of the rubber-resin adhesives andhence they may be regarded as being of the rubber-resin type. An exampleis a 75:25 copolymer of z-ethyl-butyl-acrylate and ethyl acrylate.

The rubbery bases used include crude natural rubber, Buna-S typesynthetic rubber, and polyisobutylene (Vistanex). The tackifier resinsinclude rosin, ester gum, pure hydrocarbon terpene resin of C. meltingpoint ("Piccolyte), and hydrogenated indene-coumarone resin of C.melting point (Nevillite resin). Zinc oxide can be included as anopacifying and reinforcing pigment when transparency is not needed.Carbon black can be included to give a black color, and titanium dioxidepigment to give a brilliant white color. Various chromatic pigments canbe included to produce desired colors. The adhesive is prepared forcoating by churning together the rubber (cut into pieces) and the resinin a volatile hydrocarbon solvent (such as heptane) present inproportion to impart a suitable coating viscosity.

While unified paper backings are most commonly employed in masking tapes(as illustrated by the previously cited patents), use can also be madeof non-fibrous film backings (c. f. U. S. Patents Nos. 2,156,380,2,177,627, 2,328,057, 2,- 328,066, 2,444,830). All such backings arereferred to as non-woven to distinguish from cloth backings, which areundesirable and which provide fuzzy fiber and thread tips at the edgesof the tapes.

Having now described various embodiments of my invention for purposes ofillustration, but without intent to be limited thereto, what I claim isas follows:

A roll of normally tacky and pressure-sensitive masking tape consistingof a plural odd number of individual strips of said tape in edgeto-edgerelationship wound in convolute roll form on a single core, each of saidstrips being comprised of a non-woven flexible backing coated on theinner face with a layer of rubberresin type pressure-sensitive adhesive,said adhesive layers of said individual strips being c0- hered togetheralong the contiguous edges so as to hold the strips in said edge-to-edgerelationship during unwinding from the roll and application of thecomposite tape to a surface, but being readily separable afterapplication of the tape on stripping away a central strip of said tape.

CARL J. CALABRESE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,032,026 Roden July 9, 1912 1,937,858 Taber Dec. 5, 19332,057,042 McLaurin Oct. 13, 1936 2,236,527 Drew Apr. 1, 1941 2,391,539Avery Dec. 25, 1945 2,410,078 Kellgren Oct. 29, 1946 2,410,089 Lundquistet al. Oct. 29, 1946 2,438,195 Tierney Mar. 23, 1948

